environment is important factor that influences the safety of missile system. To satisfy the request of safety prediction of weapon system, the paper adopts neural network ensemble to the environment safety prediction. The input of neural network ensemble is environment factors (temperature and its variety rate, humidity and its variety rate), and the output is the result of safety evaluation. Based on the request of weapon system environment safety, virtual sample was produced because of lacking train sample. According to the simulation result, the neural network ensemble can predict the environment safety missile effectively.